There's some kind of saying in engineering that the first 80% of a project takes 80% of the time, and then the last 20% takes the other 80% of the time. A little cryptic, admittedly, but the last stage of business development -- actually getting attorneys to do it -- is often the hardest.
The initiative has to come from the top down. The attorneys, especially the associates, have to believe that the leadership really, truly isn't kidding about the importance of business development. One way to make this point is to tie it to compensation. Another is nicely illustrated here: http://www.gerryriskin.com/law-related-publications-the-seven-immutable-laws-of-change-management-law-seven.html